You're doing something wrong, there should be no gap, cranks have to be in contact with the BB to pre-load the bearings as they are not normal roller bearings, but angular contact bearings.

 

No, gxp is not a preloaded BB. The crank spindle is captured by the non drive bearing by the step in the spindle and the crank arm. The spindle floats in the bearing on the drive side. Do NOT try to close this gap and preload the bearings. It will make the BB fail.
As far as the gap goes, there should be a wavy washer to hold the bearing seal against the the bearing on the drive side if the bb has a seal that floats. Some gxp BB has caps that don't move.

 

Ok so that means I would need to fit two spacers when I fit the BB. Then it would be preloaded. Yet the fitting instructions with the BB tell me no spacers for a 73mm shell width.
I suppose I'm the fool for believing the instructions until I'd worn out several BBs!
Thanks LyNx

 

Uh, yeah Why not just give it a go and see if it solves your problem?

 

It's a crap bb. Invest in a hope one there is a reason it's 2.5x the price

Sent from my SM-G935F using Tapatalk

 

i don't think you are doing anything wrong. there are multiple posts on this issue over the past couple years. i recall that some filled the gap with o rings that they bought at hardware store. i have experienced it first hand, too. the aftermarket GXP must be sized different than the OEM. so you can either use spacers where u r not supposed to or do the hack solution of gasket or o ring where none should be. i solved my problem by switching to a Shimano crankset and BB. I suppose you could also try a small strip of duct tape across the dust cap to keep it in place. SRAM probably designed it as such for all us hacks.


Sent from my iPhone using Tapatalk

 

it is probably just a QC issue that no one has addressed as not everyone is having the issue. some that are not the proper size are making it out of the factory.


Sent from my iPhone using Tapatalk

 

Don't try to add spacers to pre-load the drive side. That is not how the GXP BB is designed. Yes it is a common problem and has been discussed at length. Ride in dry conditions? Not as big of an issue. Lot of stream crossings etc. going to have a problem. There is a thread in here somewhere on how to re-grease the GXP BB that gets them running smoothly again.

 

AFAIK from my experience, there is supposed to be a spacer and/or wavy washer to keep things how they should be, unless things have changed.

 

OK. So now I'm confused - who is right, LyNx or thenry?
Should the BB be preloaded or not...? 🤔

 

It gets wet and it then it breaks. It's useless 30$ junk get a better one

Sent from my SM-G935F using Tapatalk

 

But that was my original question - if I get a decent one, am I going to mess that one up as well due to the gap, or will it's end cap not come off? Or do I need to preload the decent one as well to stop it breaking...?

 

On most frames, there should be a gap between the right crank arm and the right bearing. This is so you can run a BB mounted chain guide, front derailleur, etc. I had the same problem and temptorarily fixed it by putting somethin rubber between the bearing and the right arm- a section of a small inner tube, rubber bands, o-rings, etc. A few appropriately-sized o-rings should do the trick.

 

I'm a fan of wheels manufacturing BB's. Awesome quality/tolerances at a good price point. Their GXP BB's ship with the wavy washer & spacer intended to take up said space as BB crankset interface will vary with different brands/combo's etc. While I guess you could say it adds some preload to the system certainly not enough to cause one iota of wear to the bearing hence the washer being wavy. Furthermore, the captured bearing will absolutely see tremendous side load so the idea that the wavy washer is going to add enough to cause premature wear is moot. Further furthermore, any good quality BB bearing is going to be an angular contact bearing designed to handle side loading in this application.

 

Agreed on all points. It was being suggested that the cranks should be in contact with the drive side bottom bracket and that statement is not the case. A wave washer to fill the gap is going to do nothing as far as side load. That said you should be bottoming out the cranks on the spindle and not the bottom bracket cups. If you hit the BB cups before you bottom out the crank to the spindle your next issue will be your cranks coming loose all the time and a ton of drag. This system is designed to let the drive side float. Taking up the space on the drive side with a wave washer still allows you to install your cranks properly and let the drive side float.

 

I have two GXP BB's: one is on a 2009 bike and the other on a 2007 (one drive side spacer on both IIRC). Both have run lots of miles in all sorts of conditions including mud, wet, dry, etc. and still spin with no drag.

I also have Chris King, Phil Wood and Shimano BB's. Only one I've crushed so far is a Phil Wood!

 

I've used an Enduro XD-15 BB on my stumpjumper for 3 or 4 seasons and have been absolutely impressed with it. I replaced a set of seals in that time frame and that's it. User friendly and easily maintained. I can disassemble, clean, fresh grease, and reassemble in 20 minutes. I usually do this 3/4 times a season. The fact that it's an outboard design necessitates frequent maintenance.

ENDURO XD-15 OUTBOARD ROAD BOTTOM BRACKET

 

Your standard GXP BB use a cartridge bearing which requires no preloading. The aftermarket GXP from Enduro uses angular contact bearings which do require preload. I'm not familiar with any other high end GXP,s and what their designs are.